You’re getting older—think of it as shifting gears rather than as a precipitous decline. It’s time to take stock and take steps to ensure a high level of cognitive function over the course of your lifetime. Sustaining a regimen of physical activity should be at the top of your list.

What’s the name of that beautiful spring flower with the gorgeous fragrance? You know the one—it grows on a bushy plant, it’s usually purple or mauve or…?

If you answered lilac without missing a beat then chances are you’re under forty.

The rest of us are all too familiar with the mild memory glitches that inevitably go along with a brain that’s begun to show its age—that’s why you occasionally forget your neighbor’s name or notice you’re experiencing a little extra trouble when it comes to absorbing and retaining new information.

Serious cognitive decline on the other hand—almost four-and-a-half-million Americans, for example, suffer from Alzheimer’s—while associated with longevity is not necessarily an inevitable aspect of growing older.

Research suggests that the aging brain may be subject to damage from toxins, dodgy circulation and inflammation but a compelling body of growing scientific evidence suggests that you can exert positive influence over the state of your gray matter by taking affirmative steps that might help you to prevent the onset of Alzheimer’s disease and vascular dementia—both of which are expected to quadruple over the next 50 years.

The trick is to start taking preventive action at mid-life, in your forties and fifties, while your efforts may still make a difference to cognition in your seventies and eighties and beyond.

So if you don’t belong to a health club, then do yourself a favor and join one. Physical exercise, particularly the kind that gets your heart pumping, is good for brain function. Daily exercise is of paramount importance and studies suggest that you should build in variety—walk, cycle, row, garden, play golf—to achieve maximum benefit.

Research from Sweden points to lung function as being a possible predictor of dementia—bolstering the argument for exercise and for not smoking.

And what’s good for the heart apparently is also good for the head.

A recent study conducted at Columbia University Medical Center in New York suggests that a traditional Mediterranean-style diet—lots of vegetables, legumes, fruit, fish, and cereal—not only reduces the risk for heart disease but may also decrease the potential for developing dementia.

“Yes, the brain is one of the key clients for the body’s blood supply and if it is reduced or interrupted, this is bad news for the brain,” says Dr. Ian Robertson, Dean of Research, Institute of Neuroscience Trinity College in Dublin, Ireland.

“In addition, the risks of certain types of dementia may be increased by high blood pressure and smoking. A small subset of dementias appears to have a particular genetic linkage.”

Protecting the health of your vascular system—keeping your blood pressure and cholesterol in check—may be the kindest thing you can do for your brain.

It’s also important to remain mentally active, stimulating the brain with new knowledge, exposures, information and challenges. Meeting different people, traveling to places unknown, attempting to master something new, such as a language, a game, an instrument or a skill increases your brain’s reservoir of activity.

And even in your seventies and eighties it may be possible to delay the progress of dementia even after onset according to a recent study conducted in Seattle, which found that 20 minutes of walking per day produced positive effect.

Practicing Mind Control:

Dr. Robertson makes the following recommendations for helping to prevent dementia based on current research:

Regular physical exercise – aerobic – in middle age predicts an approximately 60 per cent lower risk of Alzheimer’s in old age. A randomized controlled trial of aerobic exercise in the over-sixty set compared to toning, non-aerobic exercise, showed enhanced cognitive function in the exercise group, including thickening of key brain connecting fibers in the frontal lobes.

A diet rich in antioxidants through fresh fruit and vegetables also predicts a lower rate of dementia later in life. Dark fruits and vegetables (e.g. blackberries, spinach) appear to be particularly beneficial, as does fish. Saturated fats decrease cognitive function.